Campbell’s Philosophy of Rhetoric is a key text in the Enlightenment for several reasons.
Synthesizes the key concerns of rhetoric at the time
relationship of rhetoric to contemporary philosophy
practical concern for pulpit eloquence
popular interest in elocution
connection of rhetoric with literature and criticism
long standing claims of classical rhetoric
Seeks to ground rhetoric in science
Bases his rhetorical theory on the psychology of John Locke
Connects rhetoric with its classical roots
Campbell argues rhetoric is the “search for the truth” that occurs before a speaker proceeds to persuasion. Rhetoric is also “the attempt to move the will to ethical action” and it must address “all of the mind’s faculties.” In his explanation of the purpose, Campbell reconnects with several earlier rhetorical scholars in this tripartite definition.
His argument that rhetoric is the “search for the truth” belongs in the realm of Plato who used the dialectic counterpart to achieve this purpose. Also, this search for truth belongs to Aristotle who posits rhetoric as the “counterpart to dialectic.” Through Campbell’s statement of purpose, the two can live in harmony; rhetoric can present the truth in a way that would make both Plato and Aristotle agree with the definition.
Campbell’s statement that rhetoric is the “attempt to move the will to ethical action” shows a distinct connection to the rhetorical aims of Augustine’s rhetoric. *
as an art that addresses “all of the mind’s faculties,” Campbell reasserts Francis Bacon’s argument in The Advancement of Learning. Bacon sees rhetoric as a part of Reason (philosophical), Memory (historical), and Imagination (poesy). Bacon wanted education to demonstrate the use of rhetoric in all faculties of education and the mind. Campbell agrees with this because if the student of rhetoric cannot comprehend how the art works in each faculty, they cannot be certain they will address each of these faculties in the mind of their audience.
However, Campbell lists the faculties of the mind as understanding, imagination, passions, and wills. This differs slightly from Bacon’s faculties, but the most important (for Bacon–reason and for Campbell–understanding) work harmoniously together. Reason is required for understanding, so it could be argued that the two of these facets of the same faculty.
Persuading an Audience - the orator “must excite some desire or passion in the hearers.” Then, the orator “must satisfy their judgment that there is a connection between the action to which he would persuade them, and the gratification of the desire or passion which he excites”
echoes the advice given by Cicero in De Oratore. Cicero writes that the “cardinal sin is to depart from the language of everyday life and the usage approved by the sense of the community.” Campbell expands on this by creating a hierarchy of usage:
reputable -the generally accepted customary usage of educated people and well-regarded writers. This is the language reserved for the highly trained to use in speech. Common people have a tendency to pick up “pretty” words and misuse these in their speech.
National -usage and pronunciation most widely understood through a country (and again, by the educated class)
national use includes terms of dialect that vary from region to region. It is important to remember the pure form of the word in oratory and written discourse.
Present -both foreign, faddish, or obsolete; this is largely comprised of slang and is to be avoided in discourse.
Philosophy and Rhetoric - “The rhetorician appeals to the understanding just as the logician does; moral knowledge and scientific knowledge rest on the same mental operations; the difference between moral and scientific knowledge is a question not of certainty versus probability but of the degree of probability.” In short, the real difference lies only in the subject matter
The Sequence of Persuasion - Campbell follows Bacon in outlining the sequence of persuasion:
Campbell, George. The Philosophy of Rhetoric
(1776)